Many search engine services, such as Google and Overture, allow users to search for information that is accessible via the Internet. These search engine services allow users to search for display pages, such as web pages, that may be of interest to users. After a user submits a search request (i.e., a query) that includes search terms, the search engine service identifies web pages that may be related to those search terms. To quickly identify related web pages, the search engine services may maintain a mapping of keywords to web pages. This mapping may be generated by “crawling” the web (i.e., the World Wide Web) to identify the keywords of each web page. To crawl the web, a search engine service may use a list of root web pages to identify all web pages that are accessible through those root web pages. The search engine service can identify keywords of any particular web page using various well-known information retrieval techniques, such as identifying the words of a headline, the words supplied in the metadata of the web page, the words that are highlighted, and so on. The search engine service then creates an index that maps keywords to web pages.
To identify the web pages that may be related to a search request, the search engine service uses the index to find web pages with keywords that best match the search request. The search engine service may generate a relevance score to indicate how relevant the information of the web page may be to the search request based on the closeness of each match, web page importance or popularity (e.g., Google's PageRank), and so on. The search engine service then displays the search results to the user as links to those web pages in an order that is based on a ranking determined by their relevance. The search engine services typically also display textual excerpts derived from each web page alongside the links. The textual excerpt may include the title of the web page, summary associated with the web page, portions of the web page that contain the words of the search request, and so on. Based on review of the textual excerpts and the rankings, the user can select web pages to view.
Users often need to select and view many web pages of a search result before locating a web page of interest for various reasons. One reason is that the ranking may not accurately represent the relevance of the web page. For example, an attorney who submits the query “L.A. court time” may get the same query result as an athlete who submits the same query. In such a case, web pages related to superior court times in Los Angeles County may be relevant to the attorney, but irrelevant to the athlete who may be interested in web pages related to sport court times of the Los Angeles Parks and Recreation Department. A search engine service may not know whether the user is interested in law or sports and thus cannot always rank the web pages based on the relevance to the user. Another reason that users may need to view many web pages before finding one of interest is that the textual excerpt displayed with the query result may not provide enough information to determine the relevance of the web page. For example, the textual excerpt of a query result may state, “This web page helps you check on L.A. court times at your convenience . . . if you need to arrange a court time . . . . Please arrive 15 minutes before your scheduled court time.” In such a case, the user may not know whether the web page is about legal or sport courts.
When users cannot quickly find web pages of interest using a search engine service, they may stop using that search engine service and start using a different search engine service. Since search engine services may derive significant benefits from having many users use their services, the loss of users resulting from difficulties in locating web pages of interest can be a significant problem.